'Individuals demonstrated commitment by acting, on their own initiative, with greater brutality than their orders called for. Thus excess did not spring from mechanical obedience. On the contrary; its matrix was a group structure where it was expected that members exceed the limits of normal violence.' [Sofsky, 1993, p.228]
"In short, the true horror of Eichmann and his like is not that their actions were blind. On the contrary, it is that they saw clearly what they did, and believed it to be the right thing to do.
Chances are that if you've ever given such socio-behavioral dynamics much thought or analysis (or ever held a job in certain types of environs), intuition might've led you to find the conclusions of Arendt, Milgram, Zimbardo, et al., lacking. Not that Haslam & Reicher's unpacking fully unpacks the matter, but it at least points in a more astute direction.